Recent works of paintable and printed liquid crystal laser arrays demonstrate that such lasers may be readily fabricated using printed film technology. Such films may exhibit good photonic band edge characteristic and demonstrate a feasible approach for readily producing compact optical devices. In order to broaden the usefulness of such devices, output tuning of the wavelength emitted by such micro lasers may be of great importance. Consequently, the ability to tune the optical output of emulsion-based micro liquid crystal lasers may be desirable.
In typical cholesteric phases of liquid crystals (LCs), molecules self-organized to form a periodic structure through Van-de-Waals interaction. This structure, when doped with one or more laser dyes, may be suitable for low-threshold photonic band-edge lasing across the near-infrared to the ultraviolet wavebands. Due to the liquid-like and anisotropic characteristic of LCs, such lasers may be able to respond to external stimuli or fields, including stress, thermal radiation, electric fields, and photo-irradiation.
The tunability of common LC lasers may be realized by applying an electric field across the sample (electric-field-tuning) or by heating the material. Electric fields may destroy the periodic standing helical arrangement of LCs in the film, and may result in the disappearance of lasing. Heat-tuning may require complex equipment and the heating process may take a significant amount of time. Thus, alternative methods to tune the optical characteristics of such thin film liquid crystal lasers that avoid such pitfalls may prove useful.